JP6442117B1 - Manufacturing method of organic EL display device - Google Patents

Abstract

The organic EL display device (100) has a plurality of pixels, an element substrate having an organic EL element (3) arranged in each pixel, a bank layer (48) defining each pixel, and a plurality of pixels. A thin film sealing structure (10) covering the first inorganic barrier layer (12) and an organic barrier layer (14) in contact with the upper surface or the lower surface of the first inorganic barrier layer. The plurality of pixels includes a red pixel, a green pixel, and a blue pixel, and is selectively provided on the second inorganic barrier layer (16) of the thin film sealing structure on the blue pixel, and exhibits a blue polydiacetylene It further has a layer (52), and the polydiacetylene layer is a polymer of 10,12-pentacosadiynoic acid.

Description

  The present invention relates to an organic EL display device and a manufacturing method thereof.

  Organic EL (Electro Luminescence) display devices have been put into practical use. One of the characteristics of the organic EL display device is that a flexible display device can be obtained. The organic EL display device has at least one organic EL element (Organic Light Emitting Diode: OLED) for each pixel and at least one TFT (Thin Film Transistor) that controls a current supplied to each OLED. Hereinafter, the organic EL display device is referred to as an OLED display device. An OLED display device having a switching element such as a TFT for each OLED is called an active matrix OLED display device. A substrate on which TFTs and OLEDs are formed is referred to as an element substrate.

OLEDs (especially organic light-emitting layers and cathode electrode materials) are easily deteriorated by the influence of moisture, and display unevenness is likely to occur. As a technique for protecting the OLED from moisture and providing a sealing structure that does not impair flexibility, a thin film encapsulation (TFE) technique has been developed. In the thin film sealing technique, an inorganic barrier layer and an organic barrier layer are alternately laminated to obtain a sufficient water vapor barrier property with a thin film. From the viewpoint of moisture resistance reliability of the OLED display device, the WVTR (Water Vapor Transmission Rate) of the thin film sealing structure is typically required to be 1 × 10 ⁻⁴ g / m ² / day or less.

  A thin film sealing structure used in an OLED display device currently on the market has an organic barrier layer (polymer barrier layer) having a thickness of about 5 μm to about 20 μm. Thus, the relatively thick organic barrier layer also plays a role of flattening the surface of the element substrate. However, when the organic barrier layer is thick, there is a problem that the flexibility of the OLED display device is limited.

  In Patent Document 1, when forming the first inorganic material layer, the first resin material, and the second inorganic material layer in this order from the element substrate side, the first resin material is used as the first inorganic material. A thin-film sealing structure in which the protrusion is unevenly distributed (a first inorganic material layer covering the protrusion) is disclosed. According to Patent Document 1, by allowing the first resin material to be unevenly distributed around the convex portion that may not be sufficiently covered with the first inorganic material layer, intrusion of moisture and oxygen from that portion is suppressed. In addition, since the first resin material functions as a base layer for the second inorganic material layer, the second inorganic material layer is appropriately formed, and the side surface of the first inorganic material layer is formed to have an intended film thickness. It becomes possible to coat appropriately. The first resin material is formed as follows. The heated and vaporized mist-like organic material is supplied onto an element substrate maintained at a temperature of room temperature or lower, and the organic material is condensed on the substrate to form droplets. The droplet-like organic material moves on the substrate due to capillary action or surface tension, and is unevenly distributed on the boundary portion between the side surface of the convex portion of the first inorganic material layer and the substrate surface. Thereafter, the first resin material is formed at the boundary by curing the organic material. Patent Document 2 also discloses an OLED display device having a similar thin-film sealing structure.

  Since the thin film sealing structure having an organic barrier layer made of an unevenly distributed resin described in Patent Document 1 or 2 does not have a thick organic barrier layer, it is considered that the flexibility of the OLED display device is improved. .

  On the other hand, attempts have been made to improve the color reproducibility of OLED display devices. For example, Patent Document 3 discloses an optical film that can suppress a change in color depending on the viewing direction, and an OLED display device using the optical film.

International Publication No. 2014/196137 JP-A-2006-39120 Japanese Patent Laying-Open No. 2015-102811 International Publication No. 2001/39554

  However, the optical film has a problem that the color display characteristics for each pixel cannot be optimized. In particular, in an OLED display device having a microcavity structure, the thickness of an organic EL layer (for example, an organic light emitting layer) is adjusted so as to obtain optimum resonance for each pixel color (for example, Patent Documents). 4). At this time, since the thickness of the organic EL layer is optimized according to the color exhibited by each pixel, the thickness of the organic EL layer of the blue pixel is the smallest. Then, the variation in the thickness of the organic EL layer of the blue pixel is relatively larger than that of the green pixel and the red pixel. As a result, the blue color purity is lowered, and the color reproducibility of the OLED display device is lowered. There is.

  Furthermore, since the thin film sealing structure having an organic barrier layer composed of the unevenly distributed resin has irregularities on the surface, there is also a problem that it is difficult to apply an optical film uniformly.

  An object of the present invention is to provide an organic EL display device in which the color purity of a blue pixel is improved and a method for manufacturing the same.

  An organic EL display device according to an embodiment of the present invention is an organic EL display device having a plurality of pixels, and includes a substrate and a plurality of organic EL elements supported by the substrate, each of the plurality of pixels. A plurality of organic EL elements disposed on each of the plurality of organic EL elements, an element substrate having a bank layer defining each of the plurality of pixels, and a thin film sealing structure that covers the plurality of pixels. The structure includes a first inorganic barrier layer and an organic barrier layer in contact with an upper surface or a lower surface of the first inorganic barrier layer, and the plurality of pixels include a red pixel, a green pixel, and a blue pixel, and the blue pixel It further has a blue polydiacetylene layer selectively provided on the thin film sealing structure, and the polydiacetylene layer is a polymer of 10,12-pentacosadiynoic acid.

  In one embodiment, the organic barrier layer of the thin film sealing structure has a plurality of solid portions that are in contact with the upper surface of the first inorganic barrier layer and are distributed discretely, and the thin film sealing The structure further includes a second inorganic barrier layer in contact with the upper surface of the first inorganic barrier layer and the upper surfaces of the plurality of solid portions of the organic barrier layer, and the polydiacetylene layer includes the second inorganic barrier layer Is formed on top.

  In one embodiment, the polydiacetylene layer has semiconducting properties.

In one embodiment, the specific resistance of the polydiacetylene layer is 1 × 10 ⁻¹ Ωcm or less.

  In one embodiment, the organic EL display device further includes an ultraviolet absorbing layer disposed on the polydiacetylene layer.

  In one embodiment, the first inorganic barrier layer is made of silicon nitride. In one embodiment, the second inorganic barrier layer is also formed of silicon nitride.

  In one embodiment, the polydiacetylene layer has a thickness of 0.5 μm or more and 2.0 μm or less.

  In one embodiment, the peak wavelength of blue light in the transmission spectrum of the polydiacetylene layer is in the range of 460 nm to 470 nm.

  In one embodiment, the transmittance of the polydiacetylene layer at the peak wavelength of the blue light is 80% or more.

  An organic EL display device manufacturing method according to an embodiment of the present invention is the organic EL display device manufacturing method according to any one of the above, wherein the step of forming the polydiacetylene layer includes the thin film sealing structure. And then, a step of depositing 10,12-pentacosadiynoic acid on the thin film sealing structure by a mask vapor deposition method, and a step of irradiating the 10,12-pentacosadiynoic acid with an electron beam or ultraviolet rays. To do.

  In one embodiment, the step of forming the thin film sealing structure includes a step of forming a silicon nitride layer, and after forming the silicon nitride layer, the mask vapor deposition method is performed without exposing the silicon nitride layer to the atmosphere. To deposit 10,12-pentacosadiynoic acid.

  In one embodiment, the step of forming the thin film sealing structure includes the step of preparing the element substrate on which the first inorganic barrier layer is formed in a chamber, and a photocurability of vapor or mist in the chamber. A step of supplying a resin, a step of condensing the photocurable resin on the first inorganic barrier layer to form a liquid film, and irradiating the liquid film of the photocurable resin with light. The method includes a step of forming a photocurable resin layer and a step of forming the organic barrier layer by partially ashing the photocurable resin layer.

  In one embodiment, the step of forming the organic barrier layer is performed by a spray method, a spin coating method, a slit coating method, screen printing, or an inkjet method.

  According to the embodiment of the present invention, an organic EL display device with improved blue pixel color purity and a method for manufacturing the same are provided.

(A) is a typical fragmentary sectional view of the active area | region of the OLED display apparatus 100 by embodiment of this invention, (b) is a fragmentary sectional view of the TFE structure 10 formed on OLED3. It is a top view which shows typically the structure of the OLED display apparatus 100 by Embodiment 1 of this invention. (A)-(c) is typical sectional drawing of the OLED display apparatus 100, (a) is sectional drawing along the 3A-3A 'line in FIG. 2, (b) is in FIG. FIG. 3C is a cross-sectional view taken along line 3B-3B ′, and FIG. 3C is a cross-sectional view taken along line 3C-3C ′ in FIG. (A) is an enlarged view of a portion including the particle P in FIG. 3 (a), and (b) is a size of the particle P, the first inorganic barrier layer (SiN layer) covering the particle P, and the organic barrier layer. It is a typical top view showing the relation, (c) is a typical sectional view of the 1st inorganic barrier layer which covers particle P. 3 is a plan view schematically showing a bank layer 48 of the OLED display device 100. FIG. It is sectional drawing which shows typically the pixel and bank layer 48 which OLED display apparatus 100 has, (a) is sectional drawing of the blue pixel along the 6A-6A 'line in FIG. 5, (b) is a figure. 6 is a cross-sectional view of the green pixel along line 6B-6B ′ in FIG.

  Hereinafter, an OLED display device and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings. In addition, embodiment of this invention is not limited to embodiment illustrated below. For example, the organic EL display device according to the embodiment of the present invention may have, for example, a glass substrate instead of the flexible substrate.

  First, a basic configuration of an OLED display device 100 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1A is a schematic partial cross-sectional view of an active region of an OLED display device 100 according to an embodiment of the present invention, and FIG. 1B is a partial cross-sectional view of a TFE structure 10 formed on an OLED 3. It is.

  The OLED display device 100 has a plurality of pixels, and has at least one organic EL element (OLED) for each pixel. Here, for simplicity, a structure corresponding to one OLED will be described.

  As shown in FIG. 1A, an OLED display device 100 includes a flexible substrate (hereinafter sometimes simply referred to as “substrate”) 1 and a circuit (backplane) 2 including TFTs formed on the substrate 1. And an OLED 3 formed on the circuit 2 and a TFE structure 10 formed on the OLED 3. The OLED 3 is, for example, a top emission type. The uppermost part of the OLED 3 is, for example, an upper electrode or a cap layer (refractive index adjusting layer). An optional polarizing plate 4 is disposed on the TFE structure 10.

  The substrate 1 is, for example, a polyimide film having a thickness of 15 μm. The thickness of the circuit 2 including the TFT is, for example, 4 μm, the thickness of the OLED 3 is, for example, 1 μm, and the thickness of the TFE structure 10 is, for example, 1.5 μm or less.

  FIG. 1B is a partial cross-sectional view of the TFE structure 10 formed on the OLED 3. The TFE structure 10 includes a first inorganic barrier layer (for example, SiN layer) 12, an organic barrier layer (for example, acrylic resin layer) 14, and a second inorganic barrier layer (for example, SiN layer) 16. The first inorganic barrier layer 12 is formed immediately above the OLED 3. The organic barrier layer 14 is in contact with the upper surface of the first inorganic barrier layer 12 and has a plurality of solid portions distributed discretely. The second inorganic barrier layer 16 is in contact with the upper surface of the first inorganic barrier layer 12 and the upper surfaces of the plurality of solid portions of the organic barrier layer 14. The organic barrier layer 14 is transparent (when the thickness is 1 μm, the visible light transmittance is 95% or more).

For example, the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are SiN layers (for example, Si ₃ N ₄ layers) having a thickness of, for example, 400 nm, and the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are The thickness is independently 200 nm or more and 1000 nm or less. The thickness of the TFE structure 10 is preferably 400 nm or more and less than 2 μm, and more preferably 400 nm or more and less than 1.5 μm. The thickness of the organic barrier layer 14 may be about 1 μm at most, although it depends on the size of the protrusions and particles on the surface of the first inorganic barrier layer 12. The thickness of the organic barrier layer 14 is typically 200 nm or more and 500 nm or less.

  The TFE structure 10 is formed so as to protect the active area (see the active area R1 in FIG. 2) of the OLED display device 100, and at least the active area in order from the side closer to the OLED 3 as described above. The first inorganic barrier layer 12, the organic barrier layer 14, and the second inorganic barrier layer 16 are included. Note that the organic barrier layer 14 does not exist as a film covering the entire surface of the active region, but has an opening. A portion of the organic barrier layer 14 excluding the opening and where the organic film actually exists is referred to as a “solid portion”. Further, the “opening” (sometimes referred to as “non-solid portion”) does not need to be surrounded by the solid portion and includes a notch or the like, and the first inorganic barrier layer 12 is formed in the opening. And the second inorganic barrier layer 16 are in direct contact. The opening of the organic barrier layer 14 includes at least an opening formed so as to surround the active region, and the active region is in direct contact between the first inorganic barrier layer 12 and the second inorganic barrier layer 16. Part (hereinafter referred to as “inorganic barrier layer bonding part”).

  With reference to FIGS. 2 to 7, a structure and a manufacturing method of an OLED display device according to an embodiment of the present invention will be described.

  FIG. 2 is a schematic plan view of the OLED display device 100 according to the embodiment of the present invention.

  The OLED display device 100 includes a flexible substrate 1, a circuit (backplane) 2 formed on the flexible substrate 1, a plurality of OLEDs 3 formed on the circuit 2, and a TFE structure 10 formed on the OLED 3. Have. A layer in which a plurality of OLEDs 3 are arranged may be referred to as an OLED layer 3. The circuit 2 and the OLED layer 3 may share some components. An optional polarizing plate (see reference numeral 4 in FIG. 1) may be further disposed on the TFE structure 10. In addition, for example, a layer having a touch panel function may be disposed between the TFE structure 10 and the polarizing plate. That is, the OLED display device 100 can be modified to an on-cell display device with a touch panel.

  The circuit 2 includes a plurality of TFTs (not shown), a plurality of gate bus lines (not shown) and a plurality of source bus lines (not shown) each connected to one of the plurality of TFTs (not shown). Have. The circuit 2 may be a known circuit for driving the plurality of OLEDs 3. The plurality of OLEDs 3 are connected to any of the plurality of TFTs included in the circuit 2. The OLED 3 may also be a known OLED.

  The OLED display device 100 further includes a plurality of terminals 38 arranged in a peripheral region R2 outside the active region (region surrounded by a broken line in FIG. 2) R1 in which a plurality of OLEDs 3 are arranged, and a plurality of terminals 38 and a plurality of lead wirings 30 that connect either the plurality of gate bus lines or the plurality of source bus lines, and the TFE structure 10 has an active region R1 on the plurality of OLEDs 3 and on the plurality of lead wirings 30. It is formed on the side part. That is, the TFE structure 10 covers the entire active region R1 and is selectively formed on a portion of the plurality of lead-out wirings 30 on the active region R1 side. The TFE structure 10 is not covered.

  Hereinafter, an example in which the lead wiring 30 and the terminal 38 are integrally formed using the same conductive layer will be described. However, the lead wiring 30 and the terminal 38 may be formed using different conductive layers (including a laminated structure).

  Next, the TFE structure 10 of the OLED display device 100 will be described with reference to FIGS. 3A shows a cross-sectional view taken along line 3A-3A ′ in FIG. 2, FIG. 3B shows a cross-sectional view taken along line 3B-3B ′ in FIG. 2, and FIG. ) Is a cross-sectional view taken along line 3C-3C ′ in FIG.

  As shown in FIGS. 3A and 3B, the TFE structure 10 includes a first inorganic barrier layer 12, an organic barrier layer 14, a first inorganic barrier layer 12, and an organic barrier formed on the OLED 3. And a second inorganic barrier layer 16 in contact with the layer 14. The first inorganic barrier layer 12 and the second inorganic barrier layer 16 are, for example, SiN layers, and are selectively formed only in a predetermined region so as to cover the active region R1 by a plasma CVD method using a mask. In general, the surface of a layer formed by a thin film deposition method (for example, a CVD method, a sputtering method, or a vacuum evaporation method) reflects the level difference of the base. The organic barrier layer (solid portion) 14 is formed only around the convex portion on the surface of the first inorganic barrier layer 12.

  FIG. 3A is a cross-sectional view taken along the line 3A-3A ′ in FIG. The particles P are fine dust generated during the manufacturing process of the OLED display device, and are, for example, fine glass fragments, metal particles, and organic particles. When the mask vapor deposition method is used, particles P are particularly easily generated.

  As shown in FIG. 3A, the organic barrier layer (solid portion) 14 includes a portion 14 b formed around the particle P. This is because the acrylic monomer applied after forming the first inorganic barrier layer 12 is condensed and unevenly distributed around the surface of the first inorganic barrier layer 12a on the particle P (taper angle is over 90 °). is there. On the flat part of the first inorganic barrier layer 12, an opening (non-solid part) of the organic barrier layer 14 is formed.

  Here, the structure of the portion including the particles P will be described with reference to FIGS. 4A is an enlarged view of a portion including the particle P in FIG. 3A, and FIG. 4B is a diagram illustrating the particle P, the first inorganic barrier layer (SiN layer) 12 covering the particle P, and the organic material. FIG. 4C is a schematic plan view showing the size relationship with the barrier layer 14, and FIG. 4C is a schematic cross-sectional view of the first inorganic barrier layer 12 covering the particles P.

  As shown in FIG. 4C, when particles P (for example, a diameter of about 1 μm or more) P are present, cracks (defects) 12 c may be formed in the first inorganic barrier layer 12. As will be described later, this is considered to have occurred because the SiN layer 12a growing from the surface of the particle P and the SiN layer 12b growing from the flat portion of the surface of the OLED 3 collide (impinge). When such a crack 12c exists, the barrier property of the TFE structure 10 is lowered.

  In the TFE structure 10 of the OLED display device 100, as shown in FIG. 4A, the organic barrier layer 14 is formed so as to fill the cracks 12c of the first inorganic barrier layer 12, and the organic barrier layer 14 The surface continuously and smoothly connects the surface of the first inorganic barrier layer 12a on the particle P and the surface of the first inorganic barrier layer 12b on the flat portion of the OLED 3. As will be described later, the organic barrier layer 14 is formed by curing a liquid photocurable resin, and thus forms a concave surface by surface tension. At this time, the photocurable resin shows good wettability with respect to the first inorganic barrier layer 12. If the wettability of the photocurable resin with respect to the first inorganic barrier layer 12 is poor, it may be convex. In addition, the organic barrier layer 14 may be formed thinly on the surface of the first inorganic barrier layer 12a on the particle P.

  The organic barrier layer (solid portion) 14 having a concave surface continuously and smoothly connects the surface of the first inorganic barrier layer 12a on the particle P and the surface of the first inorganic barrier layer 12b on the flat portion. Therefore, the second inorganic barrier layer 16 can be formed thereon with a dense film having no defect. As described above, the organic barrier layer 14 can maintain the barrier property of the TFE structure 10 even when the particles P are present.

The organic barrier layer (solid portion) 14 is formed in a ring shape around the particles P as shown in FIG. The diameter (area equivalent circle diameter) is, for example, 1μm about particles P when viewed from the normal direction, for example, the diameter (area equivalent circle diameter) D _o of the ring-shaped solid portion is 2μm or more.

  Here, for an example in which the organic barrier layer 14 is formed only on the discontinuous portion of the first inorganic barrier layer 12 formed on the particle P, before the particle P forms the first inorganic barrier layer 12 on the OLED 3. In the example described above, the particles P may exist on the first inorganic barrier layer 12. In this case, the organic barrier layer 14 is formed only at the discontinuous portion of the boundary between the particles P existing on the first inorganic barrier layer 12 and the first inorganic barrier layer 12, and similarly to the above, the TFE structure 10 is formed. The barrier property can be maintained. The organic barrier layer 14 may be thinly formed on the surface of the first inorganic barrier layer 12a on the particle P or the surface of the particle P. In the present specification, the organic barrier layer 14 is present around the particle P with the intention of including all these aspects.

  The organic barrier layer (solid portion) 14 is not limited to the example shown in FIG. 3A, and is formed only around the convex portion on the surface of the first inorganic barrier layer 12 for the same reason as described above. Other examples where the organic barrier layer (solid portion) 14 is formed are shown below.

  Next, the structure of the TFE structure 10 on the lead wiring 30 will be described with reference to FIG. FIG. 3B is a cross-sectional view taken along line 3B-3B ′ in FIG. 2, and is a cross-sectional view of the portion 32 on the active region R <b> 1 side of the lead-out wiring 30.

  As shown in FIG. 3B, the organic barrier layer (solid portion) 14 is formed around the convex portion on the surface of the first inorganic barrier layer 12 reflecting the cross-sectional shape of the portion 32 of the lead wiring 30. Part 14c is included.

  Since the lead wiring 30 is patterned by the same process as, for example, the gate bus line or the source bus line, here, the gate bus line and the source bus line formed in the active region R1 are also shown in FIG. The lead wiring 30 has the same cross-sectional structure as the active region R1 side portion 32. However, typically, a planarization layer is formed on the gate bus line and the source bus line formed in the active region R1, and the surface of the first inorganic barrier layer 12 on the gate bus line and the source bus line is formed. No step is formed on the surface.

  The portion 32 of the lead wiring 30 may have, for example, a forward tapered side portion (inclined side portion) whose side taper angle is less than 90 °. When the lead wiring 30 has a forward tapered side surface portion, it is possible to prevent defects from being formed in the first inorganic barrier layer 12 and the second inorganic barrier layer 16 formed thereon. That is, the moisture resistance reliability of the TFE structure 10 can be improved. The taper angle of the forward taper side surface portion is preferably 70 ° or less.

  The active region R1 of the OLED display device 100 is an inorganic barrier layer bonding portion in which the first inorganic barrier layer 12 and the second inorganic barrier layer 16 are in direct contact except for a portion where the organic barrier layer 14 is selectively formed. Is substantially covered by. Therefore, the organic barrier layer 14 becomes a moisture intrusion route, and the moisture does not reach the active region R1 of the OLED display device.

  The OLED display device 100 according to the embodiment of the present invention is suitably used for, for example, high-definition small and medium smartphones and tablet terminals. In a high-definition (for example, 500 ppi) small and medium-sized (for example, 5.7 type) OLED display device, a sufficiently low resistance wiring (including a gate bus line and a source bus line) is formed with a limited line width. In addition, the cross-sectional shape parallel to the line width direction of the wiring in the active region R1 is preferably close to a rectangle (side taper angle is about 90 °). Therefore, in order to form a low resistance wiring, the taper angle of the forward tapered side surface portion TSF may be more than 70 ° and less than 90 °, or the forward tapered side surface portion TSF is not provided and the taper angle is reduced over the entire length of the wiring. It may be 90 °.

  Next, refer to FIG. FIG. 3C is a cross-sectional view of a region where the TFE structure 10 is not formed. Here, the terminal 38 also has the same cross-sectional structure as the portion 36 of the lead-out wiring 30 shown in FIG. The portion 36 of the lead wiring 30 shown in FIG. 3C may have a taper angle of about 90 °, for example.

  Next, the organic barrier layer 14 formed around the bank structure BS will be described with reference to FIGS. The organic barrier layer (solid portion) 14 is also formed around the convex portion on the surface of the first inorganic barrier layer 12 constituting the bank structure BS.

  FIG. 5 is a plan view schematically showing a plurality of pixels and the bank layer 48 included in the OLED display device 100. The OLED display device 100 includes a red pixel R, a green pixel G, and a blue pixel B. Here, an example in which pixels of three primary colors are arranged in a stripe shape is shown, but the arrangement of the pixels is not limited to this. 6A shows a cross-sectional view of the blue pixel along the line 6A-6A ′ in FIG. 5, and FIG. 6B shows a cross-sectional view of the green pixel along the line 6B-6B ′ in FIG. Show.

  As shown in FIG. 6A, the OLED display device 100 further includes a bank structure BS that defines each of the plurality of pixels. The bank structure BS has a slope surrounding each of the plurality of pixels. The plurality of solid portions of the organic barrier layer 14 include a pixel peripheral solid portion 14a that extends from a portion on the slope S12 of the first inorganic barrier layer 12 to the periphery in the pixel.

  As shown in FIG. 6A, the bank structure BS includes a bank layer (sometimes referred to as “PDL (pixel defining layer)”) 48 formed of an insulating material. The bank layer 48 is formed between the lower electrode 42 and the organic layer 44 of the OLED 3. As shown in FIG. 6A, the OLED 3 includes a lower electrode 42, an organic layer 44 formed on the lower electrode 42, and an upper electrode 46 formed on the organic layer 44. Here, the lower electrode 42 and the upper electrode 46 constitute an anode and a cathode of the OLED 3, respectively. The upper electrode 46 is a common electrode formed over the entire pixels in the active region. On the other hand, the lower electrode (pixel electrode) 42 is formed for each pixel. When the bank layer 48 exists between the lower electrode 42 and the organic layer 44, holes are not injected from the lower electrode 42 into the organic layer 44. Therefore, since the area where the bank layer 48 exists does not function as the pixel Pix, the bank layer 48 defines the outer edge of the pixel Pix.

  As shown in FIG. 5, each pixel Pix is defined by the opening of the bank layer 48. The bank layer 48 is formed in a lattice shape, for example. The side surface of the opening of the bank layer 48 has a slope having a forward tapered side surface portion TSF. The slope of the bank layer 48 surrounds each pixel. The bank layer 48 is formed using, for example, a photosensitive resin (for example, polyimide or acrylic resin). The bank layer 48 has a thickness of 1 μm to 2 μm, for example. The inclination angle θb of the slope of the bank layer 48 is 60 ° or less. If the slope angle θb of the slope of the bank layer 48 is more than 60 °, a defect may occur in a layer located on the bank layer 48. Layers located on the bank layer 48 (for example, including the organic layer 44, the upper electrode 46, the first inorganic barrier layer 12, and the second inorganic barrier layer 16) may also form the bank structure BS. Each of the layers constituting the bank structure BS may have a slope that surrounds each of the plurality of pixels. When the thicknesses of the layers formed on the bank layer 48 are all smaller than the thickness of the bank layer 48, the slope angle of the bank structure BS is almost the same as the slope angle θb of the bank layer 48. It is thought that. The first inorganic barrier layer 12 forms a bank structure BS and has a slope S12 that surrounds each of the plurality of pixels. The organic barrier layer (solid portion) 14 includes a pixel peripheral solid portion 14a that extends from a portion on the slope S12 of the first inorganic barrier layer 12 to the periphery in the pixel.

  When the pixel peripheral solid part 14a is formed, as described in PCT / JP2017 / 046472, an OLED display device having higher front luminance and directivity than conventional ones can be obtained. For reference, the entire disclosure of PCT / JP2017 / 046472 is incorporated herein by reference.

  In the central portion in the pixel, the organic barrier layer 14 is formed only in the discontinuous portion of the first inorganic barrier layer 12 formed by the particles P. That is, the organic barrier layer 14 does not exist in a portion where the particle P does not exist in the central portion in the pixel. An OLED display device in which the particles P are not present does not have an organic barrier layer at the center in the pixel. Here, the size (sphere equivalent diameter) of the particle P is typically 0.3 μm or more and 5 μm or less. On a G4.5 (730 mm × 920 mm) substrate, for example, several tens to about 100 particles may exist, and for one OLED display device (active region), there are about several particles. There are things to do. Of course, there are OLED display devices in which the particles P are not present. The organic barrier layer 14 is formed of, for example, a photocurable resin formed by curing a photocurable resin, and a portion where the photocurable resin actually exists is referred to as a “solid portion”. As described above, the organic barrier layer 14 (solid portion) is selectively formed only around the convex portion on the surface of the first inorganic barrier layer 12.

When the particle P is present at the center in the pixel, the organic barrier layer 14 is formed at the discontinuous portion formed by the particle P. As described with reference to FIG. 4B, the organic barrier layer (solid portion) 14 is formed around the particle P in a ring shape. The diameter (area equivalent circle diameter) is, for example, 1μm about particles P when viewed from the normal direction, for example, the diameter (area equivalent circle diameter) D _o of the ring-shaped solid portion is 2μm or more. For example, in the case of a 5.7 type 2560 × 1440 pixel display device (approximately 500 ppi), the pixel pitch is 49 μm. Compared with the pixel pitch, the size of the organic barrier layer (solid portion) 14 formed around the particle P and the particle P is sufficiently small. Therefore, the organic barrier layer 14 formed around the particle P (solid) The influence on the display is small because of the change in transmittance due to

  The organic barrier layer 14 can be formed, for example, by the method described in Patent Document 1 or 2. For example, in a chamber, a vapor or mist-like organic material (for example, acrylic monomer) is supplied onto an element substrate maintained at a temperature below room temperature, condensed on the element substrate, and a capillary tube of the organic material that has become liquid Due to the phenomenon or surface tension, the first inorganic barrier layer 12 is unevenly distributed at the boundary portion between the side surface of the convex portion and the flat portion. Then, the solid part of the organic barrier layer (for example, acrylic resin layer) 14 is formed in the boundary part around the convex part by irradiating the organic material with, for example, ultraviolet rays. The organic barrier layer 14 formed by this method has substantially no solid part in the flat part. Regarding the method of forming the organic barrier layer, the disclosures of Patent Documents 1 and 2 are incorporated herein by reference. At this time, the viscosity of the photocurable resin, the wettability with respect to the slope, and the like are controlled so that a liquid film is formed on the slope of the bank layer. The surface of the slope may be modified. The organic barrier layer 14 can also be formed by adjusting the thickness of the resin layer to be formed first (for example, less than 100 nm) and / or adjusting the ashing conditions (including time).

  Here, the case where particles exist under the first inorganic barrier layer 12 has been described. Similarly, when particles exist over the first inorganic barrier layer 12, similarly, only in the discontinuous portion formed by the particles. The organic barrier layer 14 having a plurality of solid portions that are discretely distributed can be formed.

  The size (sphere equivalent diameter) of the particles P that reduce the moisture resistance reliability of the TFE structure 10 is approximately 0.3 μm to 5 μm. There may be several such particles for one OLED display device (active region), and some OLED display devices do not exist. Therefore, as described in PCT / JP2017 / 042913 by the present applicant, an organic barrier layer having a solid portion that is discretely distributed only in discontinuous portions formed by particles using an inkjet method. Can be formed. Note that particles having a size of more than 5 μm are removed by washing or the like.

  That is, the step of forming the thin film sealing structure covering the plurality of organic EL elements included in the element substrate includes the step of forming the first inorganic barrier layer, and the step below or above the first inorganic barrier layer after this step. A step of detecting particles and acquiring position information for each particle; and a step of applying micro droplets of a coating liquid containing a photocurable resin to each particle based on the acquired position information by an inkjet method; After this step, the step of forming the organic barrier layer by irradiating the photocurable resin with ultraviolet rays and curing the photocurable resin, and after this step, the first inorganic barrier layer and the organic barrier layer And forming a second inorganic barrier layer on the substrate. The photocurable resin layer formed by curing the photocurable resin may be partially ashed.

  An ink jet head in which the volume of one minute droplet is on the order of 1 fL (1 fL or more and less than 10 fL) or less than 1 fL can be suitably used. 1 fL corresponds to the volume of a sphere having a diameter of approximately 1.2 μm, and 0.1 fL corresponds to the volume of a sphere having a diameter of approximately 0.6 μm. For example, an inkjet apparatus (Super Inkjet (registered trademark)) that can eject 0.1 fL micro droplets manufactured by SIJ Technology Co., Ltd. can be suitably used. For reference, the entire disclosure of PCT / JP2017 / 042913 is incorporated herein by reference.

  The organic barrier layer 14 may be formed using, for example, a spray method, a spin coat method, a slit coat method, screen printing, or an ink jet method. An ashing process may be further included. The organic barrier layer may be formed using a photosensitive resin, and mask exposure may be performed. By mask exposure, a solid portion around the pixel may be formed, and an inorganic barrier layer bonding portion in which the first inorganic barrier layer and the second inorganic barrier layer are in direct contact may be formed.

  The organic barrier layer functions not only as the TFE structure having the organic barrier layer having the solid portions having discrete distribution as described above, but also as a flattening layer having a relatively thick thickness (for example, a thickness of about 5 μm to about 20 μm). A TFE structure having A relatively thick organic barrier layer is typically formed over the active area by ink jetting. For example, a dam (wall) surrounding the entire active region is formed, and an organic material for forming an organic barrier layer is applied to the region defined by the dam (wall) by an inkjet method. The organic barrier layer formed over the entire active region is surrounded by the inorganic barrier layer junction. The inorganic barrier layer joint is formed on the side surface and / or the top surface of the dam (wall), for example. When forming a relatively thick organic barrier layer, the first inorganic barrier layer may be omitted.

Note that, as the first inorganic barrier layer and the second inorganic barrier layer, a silicon nitride (Si ₃ N ₄ ) layer having excellent barrier properties can be suitably used. In particular, a silicon nitride layer having a refractive index of 1.80 or more and 1.90 or less is preferable. In addition, a SiO ₂ layer, a SiON layer, a SiNO layer, an Al ₂ O ₃ layer, or the like can be used.

  The OLED display device 100 according to the embodiment of the present invention exhibits a blue color selectively provided on the second inorganic barrier layer 16 of the TFE 10 on the blue pixel, as schematically shown in FIG. A polydiacetylene layer 52 is further provided. The polydiacetylene layer 52 exhibiting blue narrows the spectral width of blue light emitted from the organic light emitting layer of the blue pixel and transmits it with high transmittance. That is, the polydiacetylene layer 52 exhibiting blue improves the color purity of blue. For example, the peak wavelength of blue light (wavelength with the highest transmittance) in the transmission spectrum of the polydiacetylene layer 52 is in the range of about 460 nm or more and 470 nm or less, and the transmittance at the peak wavelength is about 80% or more. By providing the polydiacetylene layer 52 exhibiting blue, it is possible to suppress a decrease in blue color purity due to variations in the thickness of the organic light emitting layer of the blue pixel. On the other hand, as schematically shown in FIG. 6B, the green pixel does not have the polydiacetylene layer 52. Similarly to the green pixel, the red pixel does not have the polydiacetylene layer 52.

  Here, the blue polydiacetylene layer 52 is a polymer of 10,12-pentacosadiynoic acid.

  For example, the polydiacetylene layer 52 is formed as follows.

After the second inorganic barrier layer 16 having the TFE structure 10 is formed, 10,12-pentacosadiynoic acid is formed on the second inorganic barrier layer 16 by, for example, a mask vapor deposition method without exposing the second inorganic barrier layer 16 to the atmosphere. (Hereinafter abbreviated as “PCDA”). At this time, the degree of vacuum in the chamber is, for example, 10 ⁻³ Pa or less, and PCDA is deposited in a state where the temperature of the second inorganic barrier layer 16 is maintained at, for example, 50 ° C. When PCDA is deposited using a vacuum evaporation method, a film having a relatively high degree of orientation can be obtained. From the viewpoint of the degree of orientation, the underlayer is preferably a SiN layer.

  Thereafter, the polydiacetylene layer 52 is obtained by irradiating PCDA with an electron beam or ultraviolet rays (for example, 250 nm or less) to polymerize PCDA. The transmission spectrum of the polydiacetylene layer 52 can be adjusted by the irradiation conditions (intensity and time) of the electron beam or the ultraviolet ray. If the relationship between the irradiation conditions and the transmission spectrum is determined according to the electron beam or ultraviolet irradiation apparatus used, a polydiacetylene layer having the desired transmission spectrum can be easily obtained. The thickness of the polydiacetylene layer 52 is preferably 0.5 μm or more and 2.0 μm, for example.

  When an electron beam is used to polymerize PCDA, a cathode (electron gun) that emits an electron beam, a focusing coil, and a deflection coil are provided in one side in a vacuum chamber, and a stage that serves as an anode (anode) is provided on the other side. The substrate on which the OLED display device 100 is formed is transported into the polymerization apparatus provided, placed on the stage, and then scanned by an electron beam on the substrate. Instead of using the stage as an anode, the upper electrode 46 of the OLED display device 100 may be used as an anode. From the viewpoint of mass productivity and cost, it is preferable to use an ultraviolet irradiation device for the polymerization.

Here, the chemical formula of PCDA is C ₂₅ H ₄₂ O ₂ and the molecular weight is 374.60. The structural formula is shown in [Chemical Formula 1].

For example, a red pixel of the OLED display device 100 emits light having a wavelength of 600 nm to 690 nm, a green pixel emits light having a wavelength of 500 nm to 590 nm, and a blue pixel emits light having a wavelength of 400 nm to 490 nm. To emit.

  In order to consider color reproducibility, when comparing the DCI (Digital Cinema Initiatives) standard and the sRGB standard, the chromaticity coordinates of the blue pixels are not particularly changed. That is, it is important that the chromaticity coordinates of the blue pixel fall within a desired value range (x = 0.150, y = 0.060, and the peak wavelength is about 460 nm or more and 470 nm or less).

  However, in an OLED display device, particularly an OLED display device having a microcavity structure, the emission wavelength of a blue pixel may deviate from the above wavelength range due to variations in the thickness of an organic EL layer (for example, an organic light emitting layer). The polydiacetylene layer 52 absorbs light deviated from the above wavelength range and transmits blue light in the above wavelength range with high transmittance. Therefore, the emission wavelength of the blue pixel falls within a desired range regardless of the thickness of the organic EL layer. As a result, it is possible to manufacture an OLED display device in which the color purity of blue pixels is improved regardless of manufacturing variations in the OLED display device.

  When ultraviolet rays are incident on the polydiacetylene layer 52, the degree of polymerization (conjugated chain length) may change and the transmission spectrum may change. Therefore, depending on the usage environment of the OLED display device 100, it is preferable to provide an ultraviolet absorbing layer on the polydiacetylene layer 52. As the ultraviolet absorbing layer, for example, a known layer such as a titanium oxide layer can be used. When the OLED display device 100 includes, for example, a circularly polarizing plate, a material that absorbs ultraviolet rays may be used for the resin layer that forms the circularly polarizing plate.

  When the mask vapor deposition method is used, the polydiacetylene layer 52 can be selectively formed only on the blue pixel. The polydiacetylene layer 52 can be selectively formed only on the blue pixel by an inkjet method using a PCDA solution. The concentration of the solution is, for example, 0.1% by mass. By adjusting the speed at which the solvent is removed, the polydiacetylene layer 52 having a high degree of orientation can be obtained. Although it does not specifically limit as a solvent which can be used for a PCDA solution, Tetrahydrofuran, toluene, xylene, dioxane, chloroform, a dichloromethane, etc., or these mixed solvents can be used. Moreover, the speed at which the solvent is removed can be adjusted by adjusting the volume ratio (partial pressure) of the solvent vapor contained in the atmosphere of the element substrate to which the PCDA solution has been applied (for example, JP 2009-224620 A). reference).

Note that the color filter used in a liquid crystal display device or the like is insulative, whereas the polydiacetylene layer 52 has semiconducting properties and thus is not easily charged. Since the voltage applied to cause the blue pixel to emit light is higher than the pixels of other colors, the blue pixel is particularly easily charged. By providing the polydiacetylene layer 52, an effect of suppressing the charging of the blue pixel is obtained. In addition, countermeasures against static electricity (Electro-Static Discharge: ESD) can be omitted or reduced. At this time, the specific resistance of the polydiacetylene layer 52 is preferably 1 × 10 ⁻¹ Ωcm or less.

  The embodiment of the present invention can be applied to an organic EL display device, particularly a flexible organic EL display device and a manufacturing method thereof.

1: Substrate (flexible substrate)
2: Circuit 3: OLED layer 4: Polarizing plate 10: TFE structure 12: First inorganic barrier layer (SiN layer)
14: Organic barrier layer 14a: Pixel peripheral solid portion 16: Second inorganic barrier layer (SiN layer)
30: Lead wiring 38: Terminal 42: Lower electrode 44: Organic layer 46: Upper electrode 48: Bank layer 52: Polydiacetylene layer 100: OLED display BS: Bank structure P: Particle Pix: Pixel R1: Active region R2: Peripheral region

Claims (10)

A method of manufacturing an organic EL display device having a plurality of pixels,
The organic EL display device includes a substrate, a plurality of organic EL elements supported by the substrate, each of the plurality of organic EL elements disposed in each of the plurality of pixels, and each of the plurality of pixels. An element substrate having a bank layer that defines a plurality of pixels, and a thin film sealing structure that covers the plurality of pixels,
The thin film sealing structure includes a first inorganic barrier layer and an organic barrier layer in contact with an upper surface or a lower surface of the first inorganic barrier layer,
The plurality of pixels includes a red pixel, a green pixel, and a blue pixel, and further includes a polydiacetylene layer exhibiting a blue color selectively provided on the thin film sealing structure on the blue pixel, acetylene layer, Ri polymer der of 10,12-pentacosadiynoic acid,
The step of forming the polydiacetylene layer includes:
After forming the thin film sealing structure, depositing 10,12-pentacosadiynoic acid on the thin film sealing structure by a mask vapor deposition method;
Irradiating the 10,12-pentacosadiynoic acid with an electron beam or ultraviolet rays;
Including
The step of forming the thin film sealing structure includes:
Preparing the element substrate on which the first inorganic barrier layer is formed in a chamber;
Supplying a vapor or mist-like photocurable resin into the chamber;
Condensing the photocurable resin on the first inorganic barrier layer to form a liquid film;
Irradiating the liquid film of the photocurable resin with light to form a photocurable resin layer; and
Forming the organic barrier layer by partially ashing the photocurable resin layer;
Manufacturing method . The step of forming the thin film sealing structure includes a step of forming a silicon nitride layer, and after forming the silicon nitride layer, the silicon nitride layer is exposed to the atmosphere without exposing the silicon nitride layer to the atmosphere by a mask vapor deposition method. depositing pentacosadiynoic acid the process of claim 1. The organic barrier layer included in the thin film sealing structure is in contact with the upper surface of the first inorganic barrier layer and has a plurality of solid portions that are discretely distributed. A second inorganic barrier layer in contact with the upper surface of one inorganic barrier layer and the upper surfaces of the plurality of solid portions of the organic barrier layer, and the polydiacetylene layer is formed on the second inorganic barrier layer The manufacturing method according to claim 1 or 2 . The manufacturing method according to claim 1, wherein the polydiacetylene layer has semiconductivity. The specific resistance of the said polydiacetylene layer is a manufacturing method of Claim 4 which is 1 * 10 < ^-1 > ohmcm or less. The polydiacetylene layer being arranged on the further an ultraviolet absorbing layer having process according to any one of claims 1 to 5. The first inorganic barrier layer is formed of silicon nitride The method according to any one of claims 1 to 6. The manufacturing method according to any one of claims 1 to 7 , wherein the polydiacetylene layer has a thickness of 0.5 µm or more and 2.0 µm or less. The manufacturing method according to any one of claims 1 to 8 , wherein a peak wavelength of blue light in a transmission spectrum of the polydiacetylene layer is in a range of 460 nm or more and 470 nm or less. The manufacturing method of Claim 9 whose transmittance | permeability in the peak wavelength of the said blue light of the said polydiacetylene layer is 80% or more.

Images